Packet switched network access is available in two different ways. For favorably low-volume users such as database searches, dial-up access is an economical method. For high-volume customers, dedicated lines are more appropriate.

Dial-up Access (X.28) - Asynchronous (X.28)

Dial-up access using a modem is possible for speeds from 300 to 2400 bits per second through the telephone network. The network includes a PAD (Packet Assembler / Disassembler) to "packatise the data", Access to the packet switched network is controlled through a confidential user access code called Network User Identification (NUI) and password.

Dedicated Access

Dedicated lines can also be provided to the PAD. Call setup times are faster than dial-up as customers do not require to dial in to the telephone network to gain access.
Protocols; - X.28 is the internationally accepted ITU-T (International Telecommunication Union) standard governing the operations of Packet switched Networks.